package com.zhaodui.fxy;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;

public class HttpPostEmulator {
    // 每个post参数之间的分隔。随意设定，只要不会和其他的字符串重复即可。
    private static final String BOUNDARY = "----------HV2ymHFg03ehbqgZCaKO6jyH";

    public String sendHttpPostRequest(String serverUrl,
                                      ArrayList<FormFieldKeyValuePair> generalFormFields,
                                      ArrayList<UploadFileItem> filesToBeUploaded) throws Exception {

        // 向服务器发送post请求

        URL url = new URL(serverUrl/* "http://127.0.0.1:8080/test/upload" */);

        HttpURLConnection connection = (HttpURLConnection) url.openConnection();

        // 发送POST请求必须设置如下两行

        connection.setDoOutput(true);
        connection.setDoInput(true);
        connection.setUseCaches(false);
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Connection", "Keep-Alive");
        connection.setRequestProperty("Charset", "UTF-8");
        connection.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + BOUNDARY);

        // 头

        String boundary = BOUNDARY;

        // 传输内容

        StringBuffer contentBody = new StringBuffer("--" + BOUNDARY);

        // 尾

        String endBoundary = "\r\n--" + boundary + "--\r\n";

        OutputStream out = connection.getOutputStream();

        // 1. 处理文字形式的POST请求

        for (FormFieldKeyValuePair ffkvp : generalFormFields)

        {

            contentBody.append("\r\n")

                    .append("Content-Disposition: form-data; name=\"")

                    .append(ffkvp.getKey() + "\"")

                    .append("\r\n")

                    .append("\r\n")

                    .append(ffkvp.getValue())

                    .append("\r\n")

                    .append("--")

                    .append(boundary);

        }

        String boundaryMessage1 = contentBody.toString();

        out.write(boundaryMessage1.getBytes("utf-8"));

        // 2. 处理文件上传

        for (UploadFileItem ufi : filesToBeUploaded)

        {

            contentBody = new StringBuffer();

            contentBody.append("\r\n")

                    .append("Content-Disposition:form-data; name=\"")

                    .append(ufi.getFormFieldName() + "\"; ") // form中field的名称

                    .append("filename=\"")

                    .append(ufi.getFileName() + "\"") // 上传文件的文件名，包括目录

                    .append("\r\n")

                    .append("Content-Type:application/octet-stream")

                    .append("\r\n\r\n");

            String boundaryMessage2 = contentBody.toString();

            out.write(boundaryMessage2.getBytes("utf-8"));

            // 开始真正向服务器写文件

            File file = new File(ufi.getFileName());

            DataInputStream dis = new DataInputStream(new FileInputStream(file));

            int bytes = 0;

            byte[] bufferOut = new byte[(int) file.length()];

            bytes = dis.read(bufferOut);

            out.write(bufferOut, 0, bytes);

            dis.close();

            contentBody.append("------------HV2ymHFg03ehbqgZCaKO6jyH");

            String boundaryMessage = contentBody.toString();

            out.write(boundaryMessage.getBytes("utf-8"));

            // System.out.println(boundaryMessage);

        }

        out.write("------------HV2ymHFg03ehbqgZCaKO6jyH--\r\n"
                .getBytes("UTF-8"));

        // 3. 写结尾

        out.write(endBoundary.getBytes("utf-8"));

        out.flush();

        out.close();

        // 4. 从服务器获得回答的内容

        String strLine = "";

        String strResponse = "";

        InputStream in = connection.getInputStream();

        BufferedReader reader = new BufferedReader(new InputStreamReader(in));

        while ((strLine = reader.readLine()) != null)

        {

            strResponse += strLine + "\n";

        }

        // System.out.print(strResponse);

        return strResponse;

    }

}
